if a program is patented, but the patent-group "released the patent under a royalty free license.", it means that anyone can write the program and then put the source code and any other stuff that has to do with it online right?

and how does one use one of those open source licenses like GNU public license or coplyleft or something? do you just put "copyright" + year + name in the source code and include a copy of the license in the zip?